- Warmer than normal temperatures continue over the next 10 days or so
- Evidence is building for a flip to cold by the 2nd week of February
- This would mean impressive cold and snow can impact the region
- Various factors including research from my winter forecast support this outcome
Good morning. As we all thaw out from the recent frigid temperatures, the natural question is will this warm weather continue. In short, it will continue for another 10 days or so then winter should return pretty boldly as we get into February. Many of the factors I look at including the research done for my winter outlook support this.
Our current pattern features all the action out west with milder temperatures in the east...
All indications are this starts to flip in about 10 days...
The rising pressures off the west coast will allow arctic air to enter the pattern again and press into the east coast. This isn't too different from the pattern that we saw from the end of December into early January that caused the brutal cold.
My winter forecast analogs support this outcome for February...
These same analogs held up well for December vs the actual outcome...
Left was my forecast right is actual for December. Not too far off.
There are also other factors such as the MJO pattern and the Stratosphere that are adding to this support for a cold February.
When we move way up into the stratosphere you can see models project that we can see some warming occur, which could push the polar vortex off its axis..
This would mean much colder temperatures for the eastern 1/3 of the country about 2.5 weeks after this happens.
A final factor to look at is the MJO. Simply put, this is a pattern of thunderstorms in the tropical Indian ocean and the Pacific that moves into different regions. Depending on the region the storms are in influences the jet stream.
Models project that it will move from its current warm regions (4,5,6,7) possibly into a region much more favorable for cold, phase 8 as we get to the end of the first week of February...
I will touch on this more as the period approaches, but for now enjoy the mild weather it is not going to last.
Willy,
ReplyDeleteFWIW, I concur with your analysis -- the temp pattern goes colder after Feb 7, negative temp anomalies in northern NJ thru the end of the month. However, we are talking about the 15 day + range, still much uncertainty as to how cold and how long the pattern lasts. The MJO isn't the only driver in the Pacific and equator zone, and isn't usually the strongest one, from what I've read. But you do have La Nina and the counter-zonal QBO equatorial winds on your side, which appear to be peaking. As to the Arctic, not sure how strong a driver that region has been so far this season. There was a strat temp spike recently, but it didn't get over the long-term average for the days in question. We've had a negative AO thru much of the January thaw since the 10th (and when temps here cooled off from the 14th to the 18th, the AO was + ). I know that the Arc Osc isn't the same as the stratospheric polar vortex, but I've read that the AO "is the surface expression of the polar vortex".
The big question is snow . . . certainly there will be some, but as to big accumulations . . . the NAO has been positive most of the winter, the 2-week forecasts continue that trend. Today's CFSv2-weekly climate runs agree with you on cold temps in February, but see somewhat negative precipitation anomalies. Citing an even less reliable source, the Accuweather February forecast shows about the same, below normal temps after the the 8th and below normal precip.
But as I said, beyond 15 days, most anything can happen. And usually does!! Jim G